Record the greatest achievements of your life, except one.
"Hey man, what's wrong? You've seemed so down in the dumps lately."
"Yeah, it's just…well, it's complicated. I'm having severe existential despair."
"Oh. Bummer. Why?"
"It's this Sony Bloggie Touch HD Camcorder."
"Really? I can't imagine it's that bad."
"No, it's great. It's got a touchscreen interface, shoots in 1920x1080 full HD, and has a nifty flip-out USB. It's great for recording all of my major achievements, like my 300 bowling game, my son's first words…"
"So what's the problem? It sounds really great."
"The problem is that I can't record my greatest achievement of all: Buying the Bloggie Touch in the first place."
"No matter how useful the 4GB built-in flash memory is, or how easy it is to view recordings on the 3.0" touchscreen, it will never let me travel back in time and let me recording myself buying it.""No, I wouldn't think so."
"Even if I could do that, the very act of recording something before it had been ordered would create an infinitely loop of paradoxes, knotting the universe and dissolving reality. So my greatest accomplishment will go forever unrecorded." *SOB*
"There, there, buddy. You can do anything you set your mind to. Maybe you can invent a time machine that avoids the paradox knotting."
"That would be quite an achievement."
"All right, I'll do it. But you have to record the whole thing for me."
"I'd be honored. And I'm unemployed."